The value of a house is normally a fraction (in my case in London, about 20%) of the value of the plot. Rebuild cost is something you see on your home insurance, and is normally much lower than market value.
Any "prominent" city and particularly London are not good examples.
In a non-main city the cost of a newly built house is basically the cost of the land + the cost of construction (done at a more industrial level, i.e. let's say a lot of 16 houses or a building with 30-40 flats is built with costs that are some 20-30% lower than those to re-build a single house/flat) + the margin of the builder/developer (which often is not exceeding 15 or 20%).
I will give you some real world costs for my area (Italy, Tuscany, non-main-city):
Plot/land (incidence on built surface) 500 Euro/m2
[1] largely this is about buying, (partially) demolishing and rebuilding an existing building as there are very few possibilites of a completely new building on a "virgin" land plot
[2] of course this depends a lot on the exact location
